1. Field of the Invention
The present invention relates to a musical tone control apparatus which is suitable for simulating a tone-generation mechanism of an non-electronic musical instrument such as the bowed stringed instrument and wind instrument.
2. Prior Art
Some of the conventionally known electronic musical instruments providing the musical tone control apparatus can control musical characteristics such as the tone color and tone volume in response to the operating speed, operating pressure and the like thereof. Some of them can also detect the key depressing velocity of the key in the keyboard to thereby control the musical tone waveform at its attack portion, while the other can detect the key depressing pressure during the key depressing period to thereby control the musical tone waveform at its sustained portion.
In general, the bowed stringed instrument such as the violin, cello and viola can designate the rise time and fall time of the musical tone by the bowing operation, independent of the pitch designating operation by the fingers of the performer. In addition, by use of the bowing velocity and bowing pressure, it is possible to impart the varied characteristics to the musical tone such that the attack portion, sustained portion and decay portion will be formed in the musical tone waveform.
In contrast, in the aforementioned conventional electronic musical instrument, the pitch, rise time, fall time of the musical tone must be determined by the key operation, so that unlike the bowed stringed instrument, it is not possible to determine the rise time and fall time of the musical tone by the bowing operation independent of the pitch designating operation. In addition, when controlling the rising waveform in response to the key depressing velocity or when controlling the sustaining waveform in response to the key depressing pressure, it is not possible to arbitrarily designate the key depressing velocity or key depressing pressure independent of the key depressing operation, which limits the waveform range to be controlled. Thus, unlike the bowed stringed instrument, the conventional electronic musical instrument cannot impart the varied characteristics to the musical tone.
Meanwhile, in the bowed stringed instrument, when applying the external force of the bow to the string at the position which is relatively close to the fixed terminal, the sound becomes relatively hard, indicating that the sound contains a plenty of higher-harmonic overtones. In contrast, when applying the external force to the string at the position which is relatively close to the middle point of the string, the sound becomes relatively soft. For example, there are provided two performance methods of the violin wherein the string-bowing point is changed, i.e., "slur ponticello" in which the bowing operation is carried out at the string position close to the bridge and "slur tasto" in which the bowing operation is carried out on the fingering board. In short, the violin positively uses the variation of tone color due to the change of the string-bowing point.
In contrast, the conventional electronic musical instrument detects the key-depressing velocity by measuring the time required to change the contact position of the switch interlocked with the key. Therefore, only one velocity information can be obtained by every key-depression. In other words, it is not possible to perform the musical tone control in response to the change of the operating velocity of the bow. Further, the movable range of the key is relatively small, which narrows the velocity range which can be designated in response to the key-depression. Therefore, it is not possible to arbitrarily designate the operating velocity of the bow within the relatively broad range.
Moreover, even if the sustained waveform is controlled in response to the key-depressing pressure, the key-depressing velocity is not reflected in the musical tone in the conventional electronic musical instrument. Therefore, it is not possible to obtain the varied performance expression corresponding to the combination of the bowing velocity, bowing pressure and string-bowing point. In other words, unlike the bowed stringed instrument, it is not possible to apply the varied expression to the musical tone.
In short, the conventional electronic musical instrument is insufficient to simulate the tone-generation mechanism of the bowed stringed instrument.